2000
#18,135
National surname rank
Recorded bearers 1,416
First available Census row
Per 100,000 0.52
Rare Last name
Casimiro
Derived from the Slavic element "mir" meaning "peace" or "world," combined with the name "Casimir."
According to the 2020 US Census Bureau surname tables, roughly 2,381 Americans carry the last name Casimiro. That puts it at #13,915 in the national surname ranking, appearing at a frequency of 0.69 per 100,000 people (about 1 in 143,954 residents).
This page is the full Name Census profile for the Casimiro surname. You will find the Census Bureau frequency data, a multi-census history view, an ancestry and ethnicity breakdown based on self-reported demographics, the name's meaning and origin where available, and answers to the most common questions people ask about this surname.
Bearers in the US
2.4K
1 in 143,954
Census rank
#13,915
2020 decennial data
Per 100,000
0.7
Frequency rate
Recorded bearers
2.1K
rare in the US
Popularity narrative
The Census Bureau recorded 2,076 bearers of the surname Casimiro in its 2020 decennial surname file. At a rate of 0.69 per 100,000 residents, it holds the 13915th position in the national surname ranking.
Among Census respondents with the surname Casimiro, the largest self-reported group is Hispanic at 64.1%. The next largest groups are White (17.1%) and Asian/Pacific Islander (14.8%).
Origin
Meaning and origin of Casimiro
The surname Casimiro is of Spanish origin, dating back to the medieval period in Spain. It is derived from the Latin name "Casimirus," which itself is a combination of the Slavic elements "kaz" meaning "to destroy" and "mir" meaning "peace." This name was likely brought to Spain during the Reconquista, when various peoples from across Europe joined the Christian forces fighting against the Moors.
One of the earliest recorded instances of the Casimiro surname can be found in the Census of Aragon from 1495, which lists a Pedro Casimiro residing in the town of Teruel. In the 16th century, records show a Juan Casimiro who was a prominent landowner in the region of Andalusia. His family's holdings included the estate of Cortijo de Casimiro, which likely took its name from this ancestor.
During the Age of Exploration, several individuals bearing the Casimiro surname were involved in Spain's colonization efforts in the Americas. Notable among these was Diego Casimiro, a conquistador who accompanied Hernán Cortés on his expedition to Mexico in 1519. Another was Alonso Casimiro, a Jesuit missionary who traveled to Paraguay in the early 1600s and helped establish several Guaraní missions there.
In the 17th century, the Casimiro name appears in connection with the Spanish Golden Age of art and literature. Miguel Casimiro was a renowned playwright and poet who was a contemporary of Lope de Vega and Calderón de la Barca. His most famous work was the 1632 play "El Caballero de Olmedo."
Moving into the 18th century, the Casimiro surname gained prominence in the military sphere. General José Casimiro led Spanish forces during the War of the Quadruple Alliance against France, Britain, and the Dutch Republic from 1718 to 1720. He is celebrated for his decisive victory at the Battle of Cape Passaro in 1718.
As the Spanish Empire expanded its reach across the globe, the Casimiro name traveled far and wide. One notable figure was Manuel Casimiro, a sailor and explorer from Cádiz who accompanied the 1779 expedition of Juan Francisco de la Bodega y Quadra to the Pacific Northwest of North America. He is credited with helping map and chart several coastal areas that would later become part of British Columbia and Alaska.
Demographics
Ancestry and ethnicity for Casimiro
Among Census respondents with the surname Casimiro, the largest self-reported group is Hispanic at 64.1%. The next largest groups are White (17.1%) and Asian/Pacific Islander (14.8%).
The bar chart below shows how Casimiro bearers described their own race and ethnicity on the 2020 Census form. The Census Bureau groups responses into six broad categories: White, Black or African American, Hispanic or Latino, Asian and Pacific Islander, American Indian and Alaska Native, and Two or More Races. When a category has too few respondents for a given surname, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown for every Census year so the breakdown stays comparable over time. When the source file also includes raw headcounts, Name Census shows those alongside the percentages in the legend.
Keep in mind that these are self-reported numbers. A person's surname does not determine their race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the Casimiro surname at the time of the 2020 Census, not any inherent property of the name itself.
- Hispanic or Latino64.1% · 1,331
- White17.1% · 354
- Asian and Pacific Islander14.8% · 308
- Black or African American2.8% · 58
- Two or more races1.2% · 25
Timeline
Historical Census data for Casimiro
Casimiro appears in 3 published Census surname files: 2000, 2010, 2020. The cards below show how the name's rank and bearer count changed across each release.
2010
#14,669
National surname rank
Recorded bearers 2,027
+611 bearers (+43.1%)
Per 100,000 0.69
Rank movement Up 3,466 places
2020
#13,915
National surname rank
Recorded bearers 2,076
+49 bearers (+2.4%)
Per 100,000 0.69
Rank movement Up 754 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #18,135 | 1,416 | 0.52 | First available Census row | First available Census row |
| 2010 | #14,669 | 2,027 | 0.69 | +611 bearers (+43.1%) | Up 3,466 places |
| 2020 | #13,915 | 2,076 | 0.69 | +49 bearers (+2.4%) | Up 754 places |
For 2020, the Census Bureau published race and Hispanic-origin columns as counts rather than percentages. Name Census converts those counts back into shares so the ancestry section stays comparable with the older surname files.
Year on year
2010 vs 2020 Census
How has the Casimiro surname changed between Census years? The chart shows bearer count side by side, and the table compares rank, count, and frequency.
Census year comparison
20102020
| Metric | 2010 | 2020 | Change |
|---|---|---|---|
| Rank | #14,669 | #13,915 | 5.1% |
| Count | 2,027 | 2,076 | 2.4% |
| Per 100K | 0.69 | 0.69 | 0.7% |
Between the 2010 and 2020 Census, the number of Casimiro bearers went from 2,027 to 2,076 (+2.4% change). The surname moved up 754 positions in the national ranking, going from #14,669 to #13,915.
FAQ
Casimiro surname: questions and answers
How many people in the U.S. have the surname Casimiro?
Name Census estimates that about 2,381 living Americans carry the surname Casimiro. Using the current population baseline, that works out to roughly 1 in 143,954 residents.
How common is Casimiro?
Casimiro ranks #13,915 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 0.69 per 100,000 residents, which is about 1 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 2,076 people with the surname Casimiro. That is different from the site's living-bearer estimate (2,381), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.69 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.69 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 1 of them to have the surname Casimiro.
Has Casimiro become more or less common over time?
Between 2010 and 2020, the surname Casimiro went from 2,027 recorded bearers to 2,076. That is an increase of 49 (+2.4%). In the national ranking it rose from #14,669 to #13,915.
What does the Census say about the background of Casimiro?
Among Census respondents with the surname Casimiro, the largest self-reported group is Hispanic at 64.1%. The next largest groups are White (17.1%) and Asian/Pacific Islander (14.8%). These figures come from the 2020 Census Bureau surname tables, based on how respondents described their own race and ethnicity.
Which group reports this surname most often?
Hispanic is the largest self-reported group for the surname Casimiro in the 2020 Census, accounting for 64.1% (1,331 people in the source table).
What is the full ancestry breakdown?
Casimiro appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are Hispanic (64.1%), White (17.1%), Asian/Pacific Islander (14.8%). For 2020, the source file also published raw headcounts for each group, which is why this page can show both percentages and counts in the ancestry section.
Is this page using the latest Census data?
Yes. This page is using the latest surname file currently loaded on Name Census, which is 2020. The historical section above also keeps any older Census surname entries we have for Casimiro (2000, 2010, 2020).
Does the Census include every surname?
No. The Census Bureau only publishes surnames that appeared at least 100 times in a given decennial Census. That means very rare surnames are excluded entirely, and a surname can appear in one Census release but disappear from a later one if it falls below the reporting threshold.
Why don't the ancestry percentages always add up to exactly 100%?
There are two main reasons: rounding and suppression. The Census Bureau rounds published values, and it may suppress very small cells to protect privacy. For 2020, the Bureau also published raw group counts rather than direct percentages, so Name Census converts those counts back into shares for comparability across census years.
What does Casimiro mean?
Derived from the Slavic element "mir" meaning "peace" or "world," combined with the name "Casimir." The fuller origin note on this page goes into more detail.
Where does the surname data come from?
All surname statistics on Name Census are drawn from the US Census Bureau's decennial surname frequency tables. These files list every surname that appeared 100 or more times in the 2020 Census, along with a count, a per-100,000 rate, and a self-reported demographic breakdown. You can read the full explanation on our methodology page.
How does Name Census estimate living bearers?
For surnames, Name Census does not age cohorts the way it does for first names. Instead, it takes the Census Bureau's published frequency for Casimiro (0.69 per 100,000) and applies that rate to the current U.S. resident population to estimate how many living Americans have the surname today.
How many people are called Casimiro?
Find out how common the surname Casimiro is on our sister site HowManyOfMe.org — a quick modern estimate with the living-bearer count front and centre.